title: Negative clinical outcomes of medication resulting in emergency department visits.
abstract: OBJECTIVE
  The results of analyses of patients' health problems related to medication use have been highly variable due to various factors, such as different study methodology, diverse variables determined, fields of study. The aim of our study was to determine the prevalence and preventability of negative clinical outcomes of medication (NCOMs).
  
  
  METHODS
  This was a cross-sectional study performed in the emergency departments (EDs) of nine Spanish hospitals during a 3-month period. A two-stage probabilistic sampling method was used , and a systematic appraisal tool was used to identify the NCOMs based on information gathered through patient interview and review of the medical records. Case evaluations were conducted in two phases by pharmacists and physicians. The prevalence and preventability of NCOM were calculated. A homogeneity test was performed to assess potential differences in the prevalence for each hospital.
  
  
  RESULTS
  A total of 4,611 patients were included in the study. The overall prevalence of NCOMs was 35.7 % [95 % confidence interval (CI) 33.3-38.1]. These NCOMs could be divided into three categories: ineffectiveness (18.2 %; 95 % CI 16.2-20.1), necessity (14.9 %; 95 % CI 13.4-16.6), and lack of safety (2.4 %; 95 % CI 1.9-2.8). About 81 % (95 % CI 80.1-82.3) of the NCOMs could have been prevented.
  
  
  CONCLUSIONS
  NCOMs provoked approximately one-third of visits to the EDs, and a high percentage of these were preventable. Implementation of strategies for patient safety and pharmaceutical care could help to prevent these problems and optimize the use of medications.
authors.affiliation: Pharmaceutical Care Research Group, University of Granada, Campus de la Cartuja, 18071, Granada, Spain.
authors.forename: María Isabel
authors.initials: MI
authors.lastname: Baena
authors.forename: Paloma C
authors.initials: PC
authors.lastname: Fajardo
authors.forename: Antonio
authors.initials: A
authors.lastname: Pintor-Mármol
authors.forename: M José
authors.initials: MJ
authors.lastname: Faus
authors.forename: Rosario
authors.initials: R
authors.lastname: Marín
authors.forename: Antonio
authors.initials: A
authors.lastname: Zarzuelo
authors.forename: José
authors.initials: J
authors.lastname: Martínez-Olmos
authors.forename: Fernando
authors.initials: F
authors.lastname: Martínez-Martínez
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D064420:Drug-Related Side Effects and Adverse Reactions / Q000453:epidemiology* / Q000517:prevention & control; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D055815:Young Adult